Overview:
This lecture consists of the instructor lecturing for 50 minutes in an authoritative fashion on the human circulatory system. A short video clip on the circulatory system will be presented at the end of the lecture to summarize the topic visually.There will be a
tangent discussion on the popular television series “Dexter”. More specifically,
various details of his job will be explained to demonstrate to the students that
the study of blood does happen outside the classroom. A take-home crossword
will be assigned at the end of class.

Materials:
The teacher will need the class computer, projector, and screen to present the
Power Point presentation for the majority of the duration of the class (the Power Point is made available to download above). The digital media object which are used as a teaching tool in this lesson will consist
of a summary video (similar to lesson 01) and clips of the hit television show
“Dexter”, as well as the Power Point presentation.The instructor may also use the white board to further emphasize the material when they feel the need to use it. Students will need paper, pen or pencil, or their laptops to take down
notes. The Power Point presentation is made available therefore the students
must focus their notes on what is not presented on the slides.

Assessment:
A
take-home crossword will be distributed at the end of class for a total worth
of 2% of the final grade. The crossword provides questions similar to the exam
presented at the end of the 10 lectures therefore it is a great practice and
review tool. Crosswords are chosen as the method of assessment for these authoritarian
lectures because they turn a 50 min lecture into an interactive game. A lot of
material is covered in lessons set-up like this one and a crossword is more
amusing to complete than a simple questionnaire; it provides clues and to a
certain level, a confirmation of your answer. It also covers the material in as
much detail as any questionnaire. It is available for download at the top of the page.

Extra
Notes: This lecture is an introduction to the circulatory system, therefore further details (i.e. detailed composition of blood) are covered at the next biology course level. The discussion on "Dexter" will not be material for the exam.

LECTURE MATERIAL:

Outline

Closed Circulatory System (4 minutes)

Double Circulation (4 minutes)

Mammalian Circulation (10 minutes)

Blood (3 minutes)

The Heart (5 minutes)

Other Circulatory Systems (brief overview) (5 minutes)

Summary Video (3 minutes)

Science in Society (10 minutes)

Open the Power Point presentation and begin explaining the material. The white board may be used to further emphasize the material.

As you previously learned, small, non-polar
molecules such as oxygen and carbon dioxide can move between cells and their
immediate surroundings by diffusion. But diffusion is very slow for distances
of more than a few millimeters, therefore how does each cell of an animal
participate in exchange? Natural selection has resulted in two general
solutions to this problem:The first solution is a body size and shape that
keep many or all cells in direct contact with the environment. Each cell can
thus exchange materials directly with the surrounding medium (found in sponges
and cnidarians). The second solution, found in all other animals, is a circulatory
system that moves fluid between each cell’s immediate surroundings and the
tissues where exchange with the environment occurs. Today we will focus on the
mammalian circulatory system.

Closed Circulatory SystemIn a closed circulatory
system, blood is confined to vessels and is distinct from the interstitial
fluid. One or more hearts pump blood into large vessels that branch into
smaller ones coursing through the organs. Materials are exchanged between the
smallest vessels and the interstitial fluid bathing the cells. The closed circulatory system of humans and other
vertebrates is often called the cardiovascular
system. Blood circulates to and from the heart through an amazingly extensive
network of vessels. FYI: The total length of blood vessels in an average human
adult is twice Earth’s circumference at the equator!Arteries, veins, and capillaries are the three main
types of blood vessels. Arteries
carry blood away from the heart to organs throughout the body. Within organs, arteries
branch into arterioles, small
vessels that convey blood to the capillaries. Capillaries are microscopic vessels with very thin, porous walls.
Networks of these vessels, called capillary
beds, infiltrate each tissue. Across the thin walls of capillaries,
chemicals, including gas, are exchanged by diffusion. At their “downstream”
end, capillaries converge into veins,
the vessels that carry blood back to the heart. Portal veins carry blood from
capillaries in the digestive system to capillary beds in the liver. The hearts of all vertebrates contain two or more
muscular chambers. The chambers that receive blood entering the heart are
called atria. The chambers
responsible for pumping blood out of the heart are called ventricles.

Double Circulation
The circulatory systems of amphibians, reptiles, and
mammals have two distinct circuits, an arrangement called double circulation. The pumps of the two circuits serve different
tissues but are combined into a single organ, the heart. One pump, the right side of the heart, delivers
oxygen-poor blood to the capillary beds of the gas exchange tissues, where
there is a net exchange of oxygen into the blood and carbon dioxide out. This
part of the circulation is called a pulmonarycircuit. After the oxygen-enriched
blood leaves the gas exchange tissues, it enters the other pump, the left side
of the heart. Contraction of the heart propels this blood to capillary beds in
organs and tissues throughout the body. Following the exchange of oxygen and
carbon dioxide, now oxygen-poor blood returns to the heart, completing the systemic circuit.

Ask students if they have any questions up
to this point. The question period should be no more than 2-3 minutes.

Mammalian Circulation
Now let’s examine the overall organization of the
mammalian cardiovascular system.1) Contraction
of the right ventricle pumps blood to the lungs via 2) the pulmonary arteries.
As the blood flows through 3) capillary beds in the left and right lungs, it
loads oxygen and unloads carbon dioxide. Oxygen-rich blood returns from the
lungs via the pulmonary veins to 4) the left atrium of the heart. Next, the
oxygen-rich blood flows into 5) the left ventricle, which pumps the oxygen-rich
flood out to the body tissues through the systemic circuit. Blood leaves the
left ventricle via 6) the aorta, which conveys blood to arteries leading
throughout the body. The first branches of the aorta are coronary arteries,
which supply blood to the heart. Then branches lead to 7) capillary beds in the
head and arms. The aorta then descends into the abdomen, supplying oxygen-rich
blood to arteries leading to 8) capillary beds in the abdominal organs and
legs. Within the capillaries, there is net diffusion. Oxygen-poor blood from
the head, neck, and forelimbs is channeled into a large vein, 9) the superior
vena cava. Another large vein, 10) the inferior vena cava, drains blood from
the trunk and hind limbs. The two venae cavae empty their blood into 11) the
right atrium, from which the oxygen-poor blood flows into the right ventricle.

Ask students if they have any questions
regarding the pathway of blood. The question period should be held between 2-3
minutes.

Blood
composition and function:Vertebrate blood is a connective tissue consisting
of cells suspended in a liquid matrix called plasma. Dissolved in the plasma are ions and proteins that function
in osmotic regulation, transport, and defense. Plasma is composed of inorganic
salts in the form of dissolved ions, sometimes referred to as electrolytes. Suspended
in blood plasma are two classes of cells: red blood cells, which transport
oxygen, and white blood cells, which function in defense. Blood also contains platelets, fragments of cells that are
involved in the clotting process.

The
Heart:The human heart is about the size of a fist. The
contraction phase of the heart is called the systole, and the relaxation phase is called the diastole. Four valves in the heart
prevent backflow and keep blood moving in the correct direction. An Atrioventricularvalve lies between each atrium and ventricle. Semilunar valves are located at the two exits of the heart: where
the aorta leaves and the left ventricle.

Other Circulatory Systems:Briefly explain the following:

Gastrovascular Systems: animals that lack a distinct
circulatory system (found in hydras).

Open Circulatory system: the circulatory fluid, called hemolymph, is also the interstitial fluid (found in arthropods).

Single Circulation: The blood passes through the heart once in each complete
circuit (found in bony fishes and sharks).

Show summary video below. Note: Any information from the video that was NOT covered in class will NOT be exam material.

Switch gears to the "science in society" aspect of the course.

Science in Society:Provide a brief introduction of the show and the clips.“Dexter” is a psychological thriller television series which is simply genius! It is centered on Dexter Morgan who is a day-time forensic bloodstain pattern analyst and a night-time serial killer. So what does this have to do with Biology class? If you find an interest in studying blood in class, it is possible to study blood outside of class! Show the videos in order from left to right, one after the other. Emphasize that if anyone is uncomfortable watching blood videos or witnessing dead bodies, they may leave the room.

Provide a brief explanation of Dexter's job in our society.

Bloodstain
pattern analysis (BPA) is a specialty in the field of forensic science. This job demonstrates how the applications
of modern science have brought forensics to a higher level. New technologies,
especially advances in DNA analysis are available for detectives
and criminologists to use in
solving crimes.The
science of bloodstain pattern analysis applies scientific
knowledge from other fields to solve practical problems. Bloodstain pattern
analysis draws on the scientific disciplines of biology, chemistry, physics, and mathematics. Here are some of the following things a bloodstain
pattern analyst may be able to determine conclusively and state as fact:

Movement and direction of
persons or objects while they were shedding blood.

Position of persons or
objects during bloodshed.

Movement of persons or
objects after bloodshed.

The mechanism or object
used to create a specific pattern.

The direction a stain was
traveling when it was deposited.

The area of origin of an
impact pattern.

The minimum number of
impacts during an incident.

The sequence of events.

Hand out the crosswords and if there is time remaining at the end of class, allow the students to begin working on it in small groups.